A mother is sharing information about the warning signs of taking too much vitamin D.
It can be tempting to think supplements are harmless and that higher doses must be more effective, but that isn’t always true.
Going beyond the recommended daily amount of vitamin D may cause serious health problems, and the symptoms can be easy to miss at first.
Vitamin D plays a key role in keeping bones strong and supporting immune function, largely because it helps the body absorb calcium and phosphorus.
Often referred to as the “sunshine vitamin,” it’s linked to sunlight because the body can make it when skin is exposed to UVB rays.
Beyond sunshine, vitamin D is also found in foods like oily fish and fortified products, as well as in supplement form. Supplements can be particularly useful for people who struggle to maintain adequate levels, including during darker winter months.
In an interview with the BBC, mum Carys Hobbs-Sargeant explained that her son Roo was unintentionally given an excessive amount of vitamin D that had been prescribed for suspected growing pains in his legs, intended as a 12-week course.
The seven-year-old received vitamin D3 drops that were far more concentrated than expected — around seven times stronger — after two faulty batches were distributed in the UK.
The overdose led to an acute kidney injury. When Roo became suddenly unwell last year, doctors were concerned his condition could potentially be linked to something as serious as a brain tumour.
Among the symptoms noticed were weight loss and unusually high water intake.
“He became hypercalcaemic, and they were very concerned that his calcium was so high in his blood,” his mum Carys told the BBC.
“They were looking at whether it was a brain tumour, and we were sort of gearing up for him to have an MRI of his brain.”
Vitamin D toxicity is the term used for illness that can occur when too much vitamin D is taken, whether through supplements or prescribed medication. According to the Cleveland Clinic, the most significant complication is severe hypercalcemia, which can trigger problems such as vomiting, increased thirst, and frequent urination.
While it isn’t common, estimates suggest there are roughly 4,500 cases each year in the U.S.
Potential symptoms include reduced appetite, nausea and vomiting, constipation, dehydration, increased thirst, frequent urination, confusion, lethargy and fatigue, muscle weakness, trouble walking, bone pain, and kidney stones.
The Cleveland Clinic notes that treatment is mainly aimed at bringing down high calcium levels in the blood.
Care often starts with stopping all vitamin D and calcium supplements. If dehydration is present, intravenous (IV) fluids may be given. In more severe situations, doctors can also prescribe medications — including corticosteroids and bisphosphonates — to reduce bone resorption and help lower calcium levels.
A separate report published in BMJ Case Reports also detailed a case in which a man required hospital admission due to extremely high vitamin D consumption.